Stock Transactions and Unit Redemptions - Changes in Shares of Class A Common Stock Outstanding (Detail) - shares	1 Months Ended			3 Months Ended							12 Months Ended
	Dec. 31, 2022	Nov. 30, 2022	Oct. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share issuances:
Redemptions/exchanges of limited partnership interests (in shares)											30,998,136	58,024,858	13,190,311
Treasury stock repurchases (in shares)	(1,804,000)	(3,834,000)	(307,000)	(12,397,000)	(8,745,000)	0	(26,313,000)	(24,433,000)	(16,542,000)	(965,000)	(27,087,000)	(68,253,000)
Forfeitures of restricted BGC Class A common stock (in shares)											(66,000)	(140,000)
Limited Partnership
Share issuances:
Number of units redeemed and cancelled for exchange (in shares)											21,400,000	29,700,000
Class A Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at beginning of period (in shares)						317,023,000				323,018,000	317,023,000	323,018,000
Share issuances:
Redemptions/exchanges of limited partnership interests (in shares)											30,998,000	58,025,000
Vesting of RSUs (in shares)											3,284,000	2,167,000
Acquisitions (in shares)											1,206,000	1,789,000
Other issuances of BGC Class A common stock (in shares)											501,000	417,000
Treasury stock repurchases (in shares)											(27,086,884)	(68,253,498)	(2,259)
Forfeitures of restricted BGC Class A common stock (in shares)											(67,000)	(140,000)
Shares outstanding at end of period (in shares)	325,858,000						317,023,000				325,858,000	317,023,000	323,018,000
Common stock, shares issued (in shares)											20,900,000	27,500,000